December 2020 QQ: Emicixumab Responses

Here are the responses to our December, 2020 Quick Question: “What therapeutic does your center use for hemophilia A patients with inhibitors who bleed during emicizumab therapy?” There were only 6 voters Activated prothrombin complex concentrate [APCC]: 0 Recombinant activated factor VII [rFVIIa]: 4 Low-dose factor VIII: 1 High-dose factor VIII: 0 None, we see […]

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Bleeding Disorders

Dec 21 2020

george

CLS Journal Hemostasis Articles

A recent 2020 Clinical Laboratory Science Journal, publication of the American Society for Clinical Laboratory Science, offers the following hemostasis-related articles, purchasable for $5 each: Nardi MA. Emicizumab and the clinical laboratory. DOI: https://doi.org/10.29074/ascls.119.002204 Ketelson B. Molecular action of ADAMTS13 and transfusion therapies of thrombotic thrombocytopenia pupura. DOI: https://doi.org/10.29074/ascls.120.002287 Ketelson B. An overview of the […]

Bleeding Disorders

December 2020 Quick Question: Emicizumab

Our December, 2020 Quick Question addresses the uncommon incidence of breakthrough bleeds in hemophilia A patient who are being treated with emicizumab [HEMLIBRA], the immunotherapeutic that bypasses factor VIII. Treatment may become an issue in severe hemophilia in which patients develop inhibitors. See our November 29 post, Emicizumab Laboratory Assay Review [click] for some hints […]

Bleeding Disorders

November 2020 QQ: VWF Activity Assay Responses

Our November, 2020 Quick Question attracted 37 participants. Here is the stem: “Which VWF activity assay is preferred at your facility [check 10-31-20 post]?” The selections were… VWF:RCo: 58% [21] VWF:GP1bR: 3% [1] VWF:GP1gM: 14% [5] VWF:Ab: 3% [1] VWF:CBA: 22% [8]* The time-honored Ristocetin cofactor assay remains the most prevalent of VWF activity assays. […]

Bleeding Disorders

Emicizumab Laboratory Assay Review

Here is a comprehensive review of the 2017 hemophilia A therapeutic emicizumab [HEMLIBRA]. The author, Michael A. Nardi, MD, NYU Langone Health, details the effects of emicizumab on standard clot-based laboratory assays and the need for chromogenic substrate test methods. Click Nardi MA. Emicizumab and the clinical laboratory. Clin Lab Sci 2017; 30.DOI: https://doi.org/10.29074/ascls.119.002204.

Bleeding Disorders

November 2020 Quick Question: VWF Activity Assay

Our November, 2020 Quick Question asks, what von Willebrand factor activity assay is being used in your facility? Click here for the ISTH summary: Bodo I, Eikenboom J, Montgomery R, et al. Platelet-dependent von Willebrand factor activity. Nomenclature and methodology: communication from the SSC of the ISTH. J Thromb Haemost. 2015; 13:1345–50. doi:10.1111/jth.12964; or click […]

Bleeding Disorders

Factor IX Assay Unexpected Results

Mike Meyer asks, “we run three dilutions for all of our factor testing. Occasionally, we see results in which upon higher dilutions, the factor value decreases after adjusting for the dilution. For instance, I had a case today in which the FIX values were 0.64, 0.55, and 0.43 U/mL for the 1:10, 1:20, and 1:40 […]

Bleeding Disorders

Mixing Studies

A note from colleague Kathy Robinson that deserves a thorough discussion… “I am updating our mixing study procedure and have some questions…” 1. What is the lower limit at which it is useless to perform studies for both PT & PTT [APTT]? There is no firm agreement about the limit. Some perform mixes whenever the […]

Bleeding Disorders

WFH Guidelines: Third Edition

On August 4, 2020 the World Federation of Hemophilia announced the publication of the WFH Guidelines for the Management of Hemophilia, 3rd edition, 2020 [click for the publication]. The guidelines were developed by a team of experts from around the world and have been updated to reflect important developments in the management of hemophilia since […]

Bleeding Disorders

Chromogenic Factor VIII Assay FDA-Cleared

On Monday, July 20, Fritsma Factor sponsor Precision BioLogic Inc. announced US FDA 510[k] clearance of their CRYOcheck™ Chromogenic Factor VIII assay. The assay had been previously approved in Canada, the European Union, Australia, and New Zealand. The assay boasts a test range from 0–200% FVIII using one standard curve and a limit of quantitation […]

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Bleeding Disorders

Bleeding Disorders

December 2020 QQ: Emicixumab Responses

CLS Journal Hemostasis Articles

December 2020 Quick Question: Emicizumab

November 2020 QQ: VWF Activity Assay Responses

Emicizumab Laboratory Assay Review

November 2020 Quick Question: VWF Activity Assay

Factor IX Assay Unexpected Results

Mixing Studies

WFH Guidelines: Third Edition

Chromogenic Factor VIII Assay FDA-Cleared

George Fritsma MS MLS

Cheat Sheets from George

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